OP0124 A REDUCED ULTRASOUND SCANNING PROTOCOL OF 3 JOINTS BILATERALLY IMPROVES PREDICTION OF INFLAMMATORY ARTHRITIS PROGRESSION IN ANTI-CCP ANTIBODIES POSITIVE INDIVIDUALS WITH MUSCULOSKELETAL SYMPTOMS
Authors: A. DI Matteo, E. De Lorenzis, L. Duquenne, J. Nam, L. Garcia-Montoya, K. Harnden, R. Chowdhury, P. Emery, K. Mankia
Journal: Annals of the Rheumatic Diseases (2023)

<h3>Background</h3> In anti-CCP positive individuals at-risk of developing rheumatoid arthritis (CCP+ at-risk), ultrasound (US) sub-clinical inflammation and bone erosions (BE) are associated with progression to clinical arthritis<sup>[1]</sup>. However, the additional value of US in predicting progression to inflammatory arthritis (IA) when compared with routinely available clinical/serological variables has not been well defined. Moreover, which and how many joints need to be scanned for optimum predictive accuracy remains unanswered, with most studies adopting extensive US protocols which are not feasible in clinical practice<sup>[1]</sup>. <h3>Objectives:</h3> 1. In CCP+ at-risk with musculoskeletal (MSK) symptoms but no clinical synovitis, to investigate the additional value of US over and above clinical/serological variables in the prediction of IA. 2. To define an attenuated US scanning protocol, suitable for routine clinical use, for predicting IA development in CCP+ at-risk. <h3>Methods</h3> The proportion of 'progressors' to IA at 24 months was evaluated in 417 CCP+ 'at-risk' with MSK symptoms from the Leeds CCP cohort, who were selected for having an US scan at baseline. The US scanning protocol included 18 joints bilaterally [elbow, wrist, MCP joints 1-5, PIP joints 1-5, knee, ankle, MTP joints 2-5]. US synovitis (grey scale ≥1 and power Doppler signal ≥1) and BE were defined according to the EULAR/OMERACT definitions. Routine demographic/clinical data were collected: age, gender, early morning stiffness (EMS) duration, hands and/or feet tenderness on physical examination, anti-CCP antibodies level and rheumatoid factor (RF) status. Two initial multivariable binary regression models with 10-fold cross-validation for IA development at 24 months included all the clinical/serological variables associated with the outcome ("clinical" model) isolated and in combination with US synovitis and/or BE in any of the 36 joints ("clinical-US full" model). Further models explored the prediction accuracy of the clinical variables and US findings (i.e., synovitis and/or BE) in each single joint to identify the most informative scanning sites according to Akaike Information Criterion (AIC). A final model which included clinical/serological predictors and US assessment of 3 joints bilaterally ("clinical-US short" model) was compared to the "clinical-US full" model. The most predictive joints were included in this "short" model only if determining an improvement in the prediction performance (reduction in AIC≥2). <h3>Results</h3> Of the 417 CCP+ at-risk, 92 (22.1%) progressed to IA within 24 months. The following clinical/serological variables were associated with IA development at univariate analysis: age, smoking exposure, EMS duration ≥60 minutes, hands tenderness, RF positivity and high-level anti-CCP antibodies (all p&lt;0.05). Moreover, US synovitis and BE in ≥1 of 36 joints were also associated with IA progression (p&lt;0.01). The "clinical-US full" model (AUC 0.785, AIC 380.15) performed better than the "clinical" model (AUC 0.713, AIC 409.51) (p&lt;0.001) showing an adjusted odds ratio (OR) for IA onset of 3.16 (95% IC 1.79-5.58) for US synovitis and 2.83 (95% IC 1.35-5.93) for BE. The developed "clinical-US short" model - that included US assessment of wrists, knees and MTP5 joints – performed better than the "clinical" model (p&lt;0.001) and similarly (AUC 0.781, AIC 381.41) to the "clinical-US full" model (ΔAIC&lt;2) (Figure 1). <h3>Conclusion</h3> In CCP+ at-risk with MSK symptoms, US of only 3 joints bilaterally (wrist, knee and MTP5 joint) improved prediction of IA over and above clinical and serological risk factors, performing similarly to an extended research US protocol. This shortened 6 joint US protocol may offer clinically feasible risk prediction, which could be easily incorporated into routine clinical practice. <h3>Reference</h3> [1]Di Matteo A, et al. What Is the Value of Ultrasound in Individuals 'At-Risk' of Rheumatoid Arthritis Who Do Not Have Clinical Synovitis? Healthcare (Basel). 2021. <h3>Acknowledgements:</h3> NIL. <h3>Disclosure of Interests</h3> Andrea Di Matteo: None declared, Enrico De Lorenzis: None declared, Laurence Duquenne: None declared, Jacqueline Nam: None declared, Leticia Garcia-Montoya: None declared, Kate Harnden: None declared, Rahaymin Chowdhury: None declared, Paul Emery Speakers bureau: BMS, AbbVie, MSD, Pfizer, Novartis, and Roche, Abbvie, Gilead, Lilly, Novartis, Grant/research support from: AbbVie, BMS, Lilly, Samsung, Kulveer Mankia Speakers bureau: Abbvie, Lilly, UCB, Grant/research support from: Gilead, Lilly.